Hauke Marxsen was observing that cedar fumes caused oil to solidify.
That is called "camphoration" in some old books. As a matter of fact,
you can make powdered camphor by first adding a little alcohol, and
then some kind of petroleum product. When you grind it up. you get a
fine white powder that doesn't stick together. Fumes of camphor do the
same things, over a longer period of time, of course.
Camphor was also used to powder a number of things, but it was
expensive, so the old chemists knew there's also a substitute for
camphor using distilled turpentine. They treated it with hydrochloric
acid fumes and made a solid out of it, just like they would have done
with camphor, first. That makes a monochlorhydrate. Then they
purified the powder in an autoclave at high heat and pressure, mixing
it with caustic soda which extracts and holds all the sodium and salts
they don't want. After separating and washing, they ended up with
artificial camphor, which they then used in making celluloid for the
old silent flicks.
If Hauke wants to use the cedar box, he might switch to oils which
don't contain natural parrafins, and to be safe, he should also coat
the inside of the box with natural shellac made from flakes and
alcohol. Several coats will do the trick. But make _very sure_ that
the shellac coating is fully dry, first! The gummy oil can be cleaned
off with kerosene and wiped or blown dry.
As far as which oils to use, I'd say a fine synthetic, lightweight oil
for use on light parts in extreme environment-- even a good fishing
reel oil or some gun oils, should work. You'll have to read the
labels. If you don't see the ingredients, shy away from it. Cheap
over the counter oils are no good. The old watch oils would still work
well, made from whale sperm and other fish oil. And one of the best
oils in all environments still seems to be a good top lube oil for gas
tanks, like Marvel Mystery Oil. With this oil, you know it burns
without residue, so it won't camphorate.